WLAN / cellular interworking based on mobility information

ABSTRACT

In at least some embodiments, a method, apparatus, and system for performing communication using a plurality of radio access technologies (RATs) including a cellular RAT and a short-range RAT. A mobile device may be configured to receive information regarding traffic steering, i.e., cellular/short-range RAT handover, from nearby short-range access points and/or from a cellular base station. The mobile device may generate or determine mobility information of the mobile device, which indicates an amount of movement of the mobile device. The mobile device may determine whether the mobile device should transition between the cellular RAT and the short-range RAT based at least in part on the traffic-steering information and the mobility information. The mobile device may selectively transition between the cellular RAT and the short-range RAT based on the determination.

PRIORITY CLAIM

The present application claims benefit of priority to provisional patentapplication 62/140,152 titled “Wi-Fi/Cellular Internetworking Based onMobility Information” filed on Mar. 30, 2015, which is herebyincorporated by reference in its entirety as though fully and completelyset forth herein.

FIELD

The present application relates to wireless communication, and moreparticularly, to techniques relating to handovers between differentradio access technologies.

DESCRIPTION OF THE RELATED ART

Many modern smartphones and other mobile devices are capable of bothlong-range (e.g., cellular) and short-range (e.g., WLAN or Wi-Fi)connectivity. Additionally, short-range network technology iswidespread, and a number of WLAN access points in the form of eithertrusted or untrusted access points have been deployed. To leverage theavailability of WLAN technology, such as Wi-Fi, telecommunicationsstandards have defined various mechanisms related to WLAN/cellularinterworking, i.e., network utilization of both WLAN and cellularsystems to convey network traffic. These mechanisms are generallyintended to improve user connectivity, balance network traffic, andconserve device and network resources, as well as to serve otherpurposes.

Thus, at different times mobile devices may communicate using differentradio access technologies (RATs) and may selectively transition betweenthese technologies. In particular, mobile devices may perform handoverbetween cellular and Wi-Fi networks based on various criteria. However,handover processes have certain drawbacks, such as the potential todisrupt device connectivity and burden device and network resources.Thus, improvements in the field are desired.

SUMMARY

Embodiments are presented related to a mobile device, such as a userequipment device (UE), that is able to perform handovers betweenlong-range wireless networks (e.g., cellular networks) and short-rangewireless networks (e.g., WLAN or Wi-Fi networks). In some embodiments,the mobile device may comprise at least one antenna and one or moreradios coupled to the at least one antenna. The mobile device may beconfigured to communicate using a plurality of radio access technologies(RATs) including a cellular RAT and a short-range RAT, such as Wi-Fi.

The mobile device may be configured to receive information regardingtraffic steering, i.e., information usable in directing andtransitioning mobile device communications between different wirelessnetworks or RATs. This traffic-steering information may includeinformation regarding proximate access points as well as informationregarding allowable levels of device motion for handover, such asauthorized mobility states that would allow the mobile device totransition to a target network. This traffic-steering information may begenerated at least in part based on a configuration and/or estimatedrange of one or more access points proximate to the mobile device.

The mobile device may also be configured to generate informationregarding its own current or estimated state of movement, e.g., itsmobility estate. To determine its current state of motion, or mobilitystate, a mobile device may consider the number of reselection orhandover events it has performed during a time period defined by itsnetwork. The mobile device may also determine its mobility state basedon internal sensors, such as gyroscopes, and/or other locationparameters, e.g., determined from proximate Wi-Fi access points.

The mobile device may monitor and perform various measurements of thecellular and short-range networks, e.g., to determine the relativesignal strengths of signals from these networks. In some embodiments,the mobile device may only perform these measurements if a currentmobility state of the mobile device is an authorized mobility state forperforming handover, e.g., for performing cellular/Wi-Fi offloading.This may serve to reduce power expenditure, as these measurements maynot be performed if the mobility state of the mobile device is such thata transition to Wi-Fi would not be desirable, such as if the mobiledevice were moving so quickly that transitioning to the short-rangeWi-Fi access point would not be feasible.

The mobile device may then determine whether it should transitionbetween the cellular RAT and the short-range RAT based at least in parton the traffic-steering information (e.g., authorized mobility statesreceived from the network), information regarding the source and/ortarget networks (e.g., RSSI) measurements, and/or the mobility stateinformation generated by the mobile device. For example, the mobiledevice may be configured to determine whether it should transition fromthe cellular RAT to the short-range RAT based at least in part on acurrent mobility state of the mobile device being one of the authorizedmobility states for cellular/short-range RAT offloading.

In some embodiments, in determining whether the mobile device shouldtransition from the cellular RAT to the short-range RAT, the mobiledevice may be configured to compare at least one measured receivedsignal strength indicator (RSSI) of a cellular beacon signal or Wi-Fibeacon signal to a threshold. The mobile device may be configured to usea scaling factor to adjust one or more of an amount of measured RSSI oran RSSI threshold used in determining whether the mobile device shouldtransition from the cellular RAT to the short-range RAT. The at leastone scaling factor may be based on a current mobility state of themobile device such that a higher amount of Wi-Fi RSSI may be requiredfor transitioning from cellular to Wi-Fi when the mobile device is in ahigh mobility state and a lower amount of Wi-Fi RSSI may be needed fortransitioning from cellular to Wi-Fi when the mobile device is in a lowmobility state. The at least one scaling factor may be received from thecellular base station and/or modified or generated internally by themobile device.

The mobile device may then selectively perform handover, e.g.,transition between the cellular RAT and the short-range RAT, based onthe determination.

This Summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example (and simplified) wireless communicationsystem, according to some embodiments;

FIG. 2 illustrates a mobile device in communication with a cellular basestation and an access point (AP), according to some embodiments;

FIG. 3 illustrates an example block diagram of a mobile device,according to some embodiments;

FIG. 4 illustrates an example block diagram of a cellular base station,according to some embodiments;

FIG. 5 is a block diagram of an example communication system including abase station and a Wi-Fi access point, according to some embodiments;

FIG. 6 is a more detailed block diagram of an example communicationsystem including a base station and a Wi-Fi access point, according tosome embodiments;

FIG. 7 illustrates various communication components present in themobile device, according to some embodiments;

FIG. 8 illustrates various communication components present in thewireless radio manager of FIG. 7, according to some embodiments;

FIG. 9 is a flowchart diagram illustrating operation of the mobiledevice selectively transitioning from cellular to Wi-Fi, according tosome embodiments; and

FIG. 10 is a flowchart diagram illustrating operation of the mobiledevice selectively transitioning from cellular to Wi-Fi, according tosome embodiments.

While the features described herein are susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

The term “configured to” is used herein to connote structure byindicating that the units/circuits/components include structure (e.g.,circuitry) that performs the task or tasks during operation. As such,the unit/circuit/component can be said to be configured to perform thetask even when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invoke 35U.S.C. §112(f) for that unit/circuit/component.

DETAILED DESCRIPTION

The present disclosure describes embodiments in which various techniquesmay be used to improve communications that transition betweenshort-range wireless networks and long-range wireless networks.

Acronyms

The following acronyms are used in the present disclosure.

BS: Base Station

AP: Access Point

LTE: Long Term Evolution

VoLTE: Voice over LTE

IMS: IP Multimedia Subsystem

RAT: Radio Access Technology

TX: Transmit

RX: Receive

WLAN: Wireless Local Area Network

PDN: Packet Data Network

PGW: PDN Gateway

SGW: Serving Gateway

ePDG: evolved Packet Data Gateway

Glossary

The following is a glossary of terms that may be used in thisdisclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems or devices which are mobile or portable and which performswireless communications. Examples of UE devices include mobiletelephones or smart phones (e.g., iPhone™, Android™-based phones),portable gaming devices (e.g., Nintendo DS™, PlayStation Portable™,Gameboy Advance™, iPhone™), laptops, PDAs, portable Internet devices,music players, data storage devices, other handheld devices, as well aswearable devices such as wrist-watches, headphones, pendants, earpieces,etc. In general, the term “UE” or “UE device” can be broadly defined toencompass any electronic, computing, and/or telecommunications device(or combination of devices) which is easily transported by a user andcapable of wireless communication.

Mobile Device—any of various types of communication devices that aremobile and are capable of communicating on a cellular network and anon-cellular network, such as Wi-Fi. A UE is an example of a mobiledevice.

Mobility/Mobility State—The word “mobility” (and derived forms, e.g.,“mobile”) retains the full breadth of its ordinary meaning, as well asadditional meaning as intended in the art. In ordinary or non-technicallanguage the term “mobility” typically denotes an ability to move, i.e.,movability (as well as portability, etc.). However, in the context ofmobile devices and wireless communications technologies, and as usedherein, the term “mobility” may refer not only to the ability to move,but also to movement/motion itself. Thus, the “mobility state” of amobile device may refer to the state or degree of movement/motion thatthe mobile device is presently experiencing (or that the mobile deviceis determined or estimated to experience). A “high mobility state” maythen connote a state of a high level of movement, and a “low mobilitystate” may connote a low-movement state. Similarly, a mobile device maybe referred to as being “mobile” if it is moving or in motion.

Base Station—The term “Base Station” has the full breadth of itsordinary meaning, and at least includes a wireless communication stationinstalled at a fixed location and used to communicate as part of awireless cellular telephone system or cellular radio system.

Access Point—This term has the full breadth of its ordinary meaning, andat least includes a wireless communication device that offersconnectivity to a wireless local area network (WLAN), such as a Wi-Finetwork.

Wi-Fi—This term has the full breadth of its ordinary meaning, and atleast includes a wireless local area network technology based on theIEEE (Institute of Electrical and Electronics Engineers) 802.11standards, and future revisions or enhancements to those standards.

WLAN—This term has the full breadth of its ordinary meaning, and may beused to describe a variety of short-range networks, such as Wi-Finetworks.

Processing Element—refers to various elements or combinations ofelements. Processing elements include, for example, circuits such as anASIC (Application Specific Integrated Circuit), portions or circuits ofindividual processor cores, entire processor cores, individualprocessors, programmable hardware devices such as a field programmablegate array (FPGA), and/or larger portions of systems that includemultiple processors, as well as combinations of the above.

Channel/Link—a medium used to convey information from a sender(transmitter) to a receiver. It should be noted that sincecharacteristics of the term “channel” may differ according to differentwireless protocols, the term “channel” as used herein may be consideredas being used in a manner that is consistent with the standard of thetype of device with reference to which the term is used. In somestandards, channel widths may be variable (e.g., depending on devicecapability, band conditions, etc.). For example, LTE may supportscalable channel bandwidths from 1.4 MHz to 20 MHz. In contrast, WLANchannels may be 22 MHz wide while Bluetooth channels may be 1 Mhz wide.Other protocols and standards may include different definitions ofchannels. Furthermore, some standards may define and use multiple typesof channels, e.g., different channels for uplink or downlink and/ordifferent channels for different uses such as data, control information,etc.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

FIGS. 1 and 2—Communication System

FIG. 1 illustrates an example (and simplified) wireless communicationsystem. It is noted that the system of FIG. 1 is merely one example of apossible system, and disclosed embodiments may be implemented in any ofvarious systems, as desired.

As shown, the example wireless communication system includes a cellularbase station 102 which may communicate over a transmission medium withone or more mobile devices 106A, 106B, etc., through 106N. Each of themobile devices may be, for example, a “user equipment device” (UE) orother types of devices as defined above.

The base station 102 may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless cellularcommunication with the mobile devices 106A through 106N. The basestation 102 may also be equipped to communicate with a network 100(e.g., a core network of a cellular service provider, atelecommunication network such as a public switched telephone network(PSTN), and/or the Internet, among various possibilities). Thus, thebase station 102 may facilitate communication between the mobile devicesand/or between the mobile devices and the network 100.

The communication area (or coverage area) of the base station may bereferred to as a “cell.” The base station 102 and the mobile devices 106may be configured to communicate over the transmission medium using anyof various cellular radio access technologies (RATs), also referred toas wireless cellular communication technologies, or telecommunicationstandards, such as GSM, UMTS (WCDMA, TD-SCDMA), LTE, LTE-Advanced(LTE-A), 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD), Wi-Fi,WiMAX etc. A typical wireless cellular communication system will includea plurality of cellular base stations that provide different coverageareas or cells, with handoffs between cells.

Additionally, the example wireless communication system may include oneor more wireless access points (such as access point 104) which may becommunicatively coupled to the network 100. Each wireless access point104 may provide a wireless local area network (WLAN) for communicationwith mobile devices 106. These wireless access points may comprise Wi-Fiaccess points. Wireless access point 104 may be configured to supportcellular network offloading and/or otherwise provide wirelesscommunication services as part of the wireless communication systemillustrated in FIG. 1.

Cellular base station 102 and other similar base stations, as well asaccess points (such as access point 104) operating according to adifferent wireless communication standard (e.g., Wi-Fi), may thus beprovided as a network which may provide continuous or nearly continuousoverlapping service to mobile devices 106 and similar devices over awide geographic area via one or more wireless communication standards.

Thus, while base station 102 may act as a “serving cell” for a mobiledevice 106 as illustrated in FIG. 1, each mobile device 106 may also becapable of receiving signals from (and possibly within communicationrange of) one or more other cells (which might be provided by other basestations (not shown) and/or wireless local area network (WLAN) accesspoints, which may be referred to as “neighboring cells” or “neighboringWLANs” (e.g., as appropriate), and/or more generally as “neighbors”.

FIG. 2 illustrates mobile device 106 (e.g., one of the devices 106Athrough 106N) in communication with both a Wi-Fi access point 104 and acellular base station 102. The mobile device 106 may be a device withboth cellular communication capability and non-cellular communicationcapability, e.g., Wi-Fi capability, such as a mobile phone, a hand-helddevice, a computer or a tablet, a wearable device, or virtually any typeof wireless device.

The mobile device 106 may include a processor that is configured toexecute program instructions stored in memory. The mobile device 106 mayperform any of the method embodiments described herein by executing suchstored instructions. Alternatively, or in addition, the mobile device106 may include a programmable hardware element such as an FPGA(field-programmable gate array) that is configured to perform any of themethod embodiments described herein, or any portion of any of the methodembodiments described herein.

In some embodiments, the mobile device 106 may be configured tocommunicate using any of multiple radio access technologies/wirelesscommunication protocols. For example, the mobile device 106 may beconfigured to communicate using any of various cellular communicationtechnologies, such as GSM, UMTS, CDMA2000, LTE, LTE-A, etc. The mobiledevice may also be configured to communicate using any of variousnon-cellular communication technologies such as WLAN/Wi-Fi, or GNSS.Other combinations of wireless communication technologies are alsopossible. The mobile device may also be able to selectively hand offbetween a cellular radio access technology (RAT) and a short-rangewireless RAT, such as Wi-Fi.

The mobile device 106 may include one or more antennas for communicatingusing one or more wireless communication protocols or technologies. Insome embodiments, the mobile device 106 might be configured tocommunicate using either of CDMA2000 (1×RTT/1×EV-DO/HRPD/eHRPD) or LTEusing a single shared radio and/or GSM or LTE using the single sharedradio. The shared radio may couple to a single antenna, or may couple tomultiple antennas (e.g., for MIMO) for performing wirelesscommunications. In general, a radio may include any combination of abaseband processor, analog RF signal processing circuitry (e.g.,including filters, mixers, oscillators, amplifiers, etc.), or digitalprocessing circuitry (e.g., for digital modulation as well as otherdigital processing). Similarly, the radio may implement one or morereceive and transmit chains using the aforementioned hardware. Forexample, the mobile device 106 may share one or more parts of receiveand/or transmit chains between multiple wireless communicationtechnologies, such as those discussed above.

In some embodiments, the mobile device 106 may include separate transmitand/or receive chains (e.g., including separate RF and/or digital radiocomponents) for each wireless communication protocol with which it isconfigured to communicate. As a further possibility, the mobile device106 may include one or more radios which are shared between multiplewireless communication protocols, and one or more radios which are usedexclusively by a single wireless communication protocol. For example,the mobile device 106 might include a shared radio for communicatingusing either of LTE or 1×RTT (or LTE or GSM), and separate radios forcommunicating using each of Wi-Fi and Bluetooth. Other configurationsare also possible.

FIG. 3—Mobile Device Block Diagram

FIG. 3 illustrates an example simplified block diagram of a mobiledevice 106. As shown, the mobile device 106 may include a system on chip(SOC) 300, which may include portions for various purposes. The SOC 300may be coupled to various other circuits of the mobile device 106. Forexample, the mobile device 106 may include various types of memory(e.g., including Flash 310), a connector interface 320 (e.g., forcoupling to a computer system, dock, charging station, etc.), thedisplay 360, cellular communication circuitry 330 such as for LTE, GSM,etc., and short-range wireless communication circuitry 329 (e.g.,Bluetooth™ and WLAN circuitry). The mobile device 106 may furthercomprise one or more smart cards 312 that comprise SIM (SubscriberIdentity Module) functionality, such as one or more UICC(s) (UniversalIntegrated Circuit Card(s)) cards 312, or the SIM functionality may becontained in an embedded memory. The cellular communication circuitry330 may couple to one or more antennas, preferably two antennas 335 and336 as shown. The short-range wireless communication circuitry 329 mayalso couple to one or both of the antennas 335 and 336 (thisconnectivity is not shown for ease of illustration).

As shown, the SOC 300 may include processor(s) 302, which may executeprogram instructions for the mobile device 106, and display circuitry304, which may perform graphics processing and provide display signalsto the display 360. The processor(s) 302 may also be coupled to memorymanagement unit (MMU) 340, which may be configured to receive addressesfrom the processor(s) 302 and translate those addresses to locations inmemory (e.g., memory 306, read-only memory (ROM) 350, Flash memory 310)and/or to other circuits or devices, such as the display circuitry 304,cellular communication circuitry 330, short-range wireless communicationcircuitry 329, connector I/F 320, and/or display 360. The MMU 340 may beconfigured to perform memory protection and page table translation orsetup. In some embodiments, the MMU 340 may be included as a portion ofthe processor(s) 302.

In some embodiments, as noted above, the mobile device 106 comprises atleast one smart card 312, such as a UICC 312, which executes one or moreSubscriber Identity Module (SIM) applications and/or otherwiseimplements SIM functionality. The at least one smart card 312 may beonly a single smart card 312, or the mobile device 106 may comprise twoor more smart cards 312. Each smart card 312 may be embedded, e.g., maybe soldered onto a circuit board in the mobile device 106, or each smartcard 312 may be implemented as a removable smart card, an electronic SIM(eSIM) or any combination thereof. Any of various other SIMconfigurations are also contemplated.

As noted above, the mobile device 106 may be configured to communicatewirelessly using multiple radio access technologies (RATs). The mobiledevice 106 may be configured to communicate according to a Wi-Fi RATand/or one or more cellular RATs, e.g., such as selectivelycommunicating on the cellular RAT and Wi-Fi RAT at different times, orcommunicating on both Wi-Fi and cellular at the same time. For example,the mobile device 106 may be communicating on a primary communicationchannel (such as Wi-Fi), and in response to detected criteria, which mayinclude degradation of the primary communication channel, may establisha secondary communication channel (such as on cellular). Alternatively,the mobile device 106 may be communicating on a primary communicationchannel (such as cellular), and in response to detected criteria, whichmay include degradation of the primary communication channel, mayestablish a secondary communication channel (such as on Wi-Fi). Themobile device 106 may operate to dynamically establish and/or removedifferent primary and/or secondary communication channels as needed,e.g., to provide the best user experience while attempting to minimizecost.

As described herein, the mobile device 106 may include hardware andsoftware components for implementing the features and methods describedherein. The processing element (or processor) 302 of the mobile device106 may be configured to implement part or all of the features describedherein, e.g., by executing program instructions stored on a memorymedium (e.g., a non-transitory computer-readable memory medium).Alternatively (or in addition), processor 302 may be configured as aprogrammable hardware element, such as an FPGA (Field Programmable GateArray), or as an ASIC (Application Specific Integrated Circuit).Alternatively (or in addition) the processor 302 of the mobile device106, in conjunction with one or more of the other components 300, 304,306, 310, 320, 330, 335, 340, 350, 360 may be configured to implementpart or all of the features described herein.

FIG. 4—Base Station Block Diagram

FIG. 4 illustrates an example block diagram of a base station 102. It isnoted that the base station 102 of FIG. 4 is merely one example of apossible base station. As shown, the base station 102 may includeprocessor(s) 478 which may execute program instructions for the basestation 102. The processor(s) 478 may also be coupled to memorymanagement unit (MMU) 476, which may be configured to receive addressesfrom the processor(s) 478 and translate those addresses to locations inmemory (e.g., memory 472 and read-only memory (ROM) 474) or to othercircuits or devices.

The base station 102 may include at least one network port 480. Thenetwork port 480 may be configured to couple to a cellular network,e.g., a core network of a cellular service provider. The core networkmay provide mobility-related services and/or other services to aplurality of devices, such as mobile devices 106. In some cases, thenetwork port 480 may couple to a telephone network via the core network,and/or the core network may provide a telephone network (e.g., amongother mobile devices serviced by the cellular service provider).

The base station 102 may include at least one antenna 486, and possiblymultiple antennas. The at least one antenna 486 may be configured tooperate as a wireless cellular transceiver and may be further configuredto communicate with mobile devices 106 via wireless communicationcircuitry 482. The antenna 486 communicates with the wirelesscommunication circuitry 482 via communication chain 484. Communicationchain 484 may be a receive chain, a transmit chain or both. The wirelesscommunication circuitry 482 and the communication chain 484 may composea radio. The radio may be configured to communicate via various cellularnetwork standards, including, but not limited to UMTS, and LTE basedstandards, including LTE-Advanced. Access point 104 may also bedescribed according to the block diagram of FIG. 4, except thatcommunication may be performed using any of various Wi-Fi communicationtechnologies.

FIG. 5—Example Wireless Communication System

FIG. 5 illustrates an example wireless communication system according tosome embodiments. As shown, the mobile device 106 may communicate with acellular network via cellular base station (BS) 102. The cellular basestation 102 may communicate with a Serving Gateway (SGW) 510. In someembodiments, the SGW 510 is responsible for handovers with neighboringbase stations. As represented in the illustration, in some embodimentsSGW 510 couples to a Packet Data Network (PDN) Gateway, or (PGW) 520. Asshown, evolved Packet Data Gateway (ePDG) 530 operates to interfacebetween the cellular and Wi-Fi networks. PGW 520 assigns device IPaddresses of the iWLAN tunnel interface and the cellular interface.Together ePDG 530, SGW 510 and PGW 520 make up the evolved packet core(EPC).

As shown, mobile device 106 may also communicate with a Wi-Fi accesspoint (AP) 104, where the Wi-Fi access point presents a Wi-Fi network.The Wi-Fi access point 104 may couple through a network, such as theInternet, to the evolved Packet Data Gateway (ePDG) 530. The ePDG 530 isutilized in the network function of 4G mobile core networks, known asthe evolved packet core (EPC) mentioned above, as well as future mobilenetworks, such as 5G networks. As noted above, the ePDG 530 may act asan interface between the EPC and non-3GPP networks that may use secureaccess, such as Wi-Fi and femtocell access networks.

The PGW may function as an inter-RAT mobility anchor. The PGW 520 maycouple to an IMS (IP Multimedia Subsystem) server. The IMS server maycomprise a computer system with a processor and memory which performsvarious operations as described herein. The IMS server may implement anIMS Service Layer 540. The IMS server may also implement a Proxy CallSession Control Function (P-CSCF). The P-CSCF may act as the entry pointto the IMS domain and may serve as the outbound proxy server for themobile device. The mobile device may attach to the P-CSCF prior toperforming IMS registrations and initiating SIP sessions. The P-CSCF maybe in the home domain of the IMS operator, or it may be in the visitingdomain where the mobile device is currently roaming.

The IMS server may couple to other networks such as the public switchedtelephone network (PSTN) or other types of communication networks, e.g.,for communicating with other communication devices, such as a standardPOTS telephone (shown), another mobile device, etc.

FIG. 6—Example Wireless Communication System

FIG. 6 illustrates a more detailed example of a wireless communicationsystem. FIG. 6 illustrates a more detailed block diagram of the evolvedpacket core (EPC) having several cellular base stations, each referredto as eNodeB.

A WLAN is also shown containing two WLAN access points, referred to asWLAN APs. In particular, the WLAN APs may be Wi-Fi access points, asshown. In the illustrated system, the Wi-Fi access points are of twodiffering types: a first type coupled to a 3GPP trusted WLAN, and asecond type coupled to a 3GPP untrusted WLAN. The Wi-Fi access pointthat is coupled to the 3GPP trusted WLAN is coupled directly to the corenetwork of a cellular provider, and may be a Wi-Fi access point operatedby the cellular provider. In contrast, the Wi-Fi access point coupled tothe 3GPP untrusted WLAN may not be operated by the cellular provider,and may be any type of WLAN network.

A mobile device 106, shown in FIG. 6 as mobile device, may perform3GPP/WLAN offload between the cellular and WLAN networks, as describedfurther below. More specifically, the mobile device may be currentlycommunicating on a cellular network and may obtain information usable indetermining whether to transition to using a Wi-Fi (WLAN) network forcommunication. For example, the mobile device may be conducting a Voiceover LTE (VoLTE) call on the cellular network and may determine whetherto transition to the Wi-Fi network for the VolTE call. Alternatively,the mobile device may be currently communicating on a Wi-Fi (WLAN)network and may obtain information used in determining whether totransition to using a cellular network for communication.

FIG. 7—Mobile Device Functionality

FIG. 7 illustrates example functionality that may be present in themobile device 106. As shown, the mobile device 106 may comprise a RATblock 602 that comprises a wireless radio manager 604, a communicationcenter (CommCenter) block 606, and a Wi-Fi manager block 608. Thewireless radio manager 604 may be configured to receive variousstatistics from the communication center block 606 and/or the Wi-Fimanager block 608 and determine whether to use one or more of availablecellular and Wi-Fi connections based on the statistics, as discussedfurther below. In some embodiments, the communication block 606 maymanage or control baseband logic 610 (e.g., related to cellularcommunication), and Wi-Fi manager block 608 may manage or control Wi-Firadio 612. Although not shown, the RAT block 602 may include a symptomsmanager that may report current connection information (e.g., connectionmetrics or statistics) to the wireless radio manager 604. Elements ofthe RAT block 502 may be implemented as software or firmware executableby a processor.

FIG. 8—Mobile Device Functionality

FIG. 8 illustrates further example functionality that may be present inthe mobile device 106. More specifically, FIG. 8 illustratesfunctionality that may be contained in the wireless radio manager (iRAT)604. As shown, the wireless radio manager 604 of the mobile device 106may comprise a management engine 632, a memory 634 that stores linkpreference information, mobility state generation logic 642, scalingfactor logic 644, and RAT determination logic 646.

As shown, the wireless radio manager (iRAT) 604 may receive informationfrom the cellular network, e.g., from the cellular base station 102,regarding allowed mobility states, that is, mobility states that wouldpermit the mobile device to transition to one or more proximate Wi-Fiaccess points. The wireless radio manager (iRAT) 604 may also receiveinformation from the cellular network regarding scaling factors, whichthe mobile device may use in assessing received signal strengthinformation (RSSI) from the base station and/or proximate access points.

The wireless radio manager (iRAT) 604 may also receive or determinecellular quality metric information 1002 from the CommCenter 606, whichwas obtained from the cellular network, and may receive Wi-Fi qualitymetric information from Wi-Fi Manager 608. As discussed further below,the mobile station may use the cellular quality metric information 1002,the Wi-Fi quality metric information 1004, information regardingacceptable mobility states for transitioning from cellular to Wi-Fi, andscaling factor information, in determining whether to transition from acellular network to a Wi-Fi network.

Background: WLAN Interworking Procedures in Telecommunications Standards

Current and/or future versions of telecommunications standards havedefined various mechanisms to allow for WLAN interworking, i.e., networkutilization of both WLAN and cellular systems to convey network traffic.WLAN interworking involves selectively redirecting mobile devicecommunications between short-range networks and cellular networks. Thistransitioning between different RATs (Radio Access Technologies), e.g.,between WLAN and cellular technologies, may be referred to as mobiledata offloading (or simply offloading), traffic steering, or traffichandover (or simply handover or handoff). The term “mobile dataoffloading” may also refer more specifically to the case oftransitioning mobile devices from operating using cellular to operatingusing WLAN (e.g., Wi-Fi).

In particular, existing telecommunications standards allow for thefollowing features related to WLAN interworking and traffic steering:(1) discovery of cellular operators' WLAN access points using cellularindications; and (2) traffic handover between cellular and WLAN for thepurpose of balancing network traffic. To assist in determining when orwhether a mobile device (e.g., mobile device 106) should initiatetraffic handover, as well as to assist in performing handover, variousconditions and items of information may be considered. For example, the3GPP Release 12 Framework outlines a procedure for RAN-assisted WLANinterworking, whereby RAN assistance is used to facilitate trafficsteering between E-UTRAN (Evolved UMTS Terrestrial Radio Access Network,associated with LTE) and WLAN.

According to the 3GPP Release 12 Framework, RAN assistance parametersmay be provided to the mobile device using SystemInformationBlockType17or RRCConnectionReconfiguration items. When current RAN assistanceparameters undergo changes, upper layer protocols of the mobile devicemay be notified. Whether certain conditions involving these parametersare satisfied may dictate traffic steering, i.e., when, whether, or howtraffic handover should occur. These traffic-steering rules and RANassistance parameters, as described in the 3GPP Release 12 Framework,are further outlined below.

Namely, according to the 3GPP Release 12 Framework, the following RRC(Radio Resource Control) rules may be used to determine offloading fromLTE (or E-UTRAN) to WLAN:

1. In the E-UTRAN serving cell:

-   -   RSRPmeas<Thresh_(ServingOffloadWLAN, LowP); or    -   RSRQmeas<Thresh_(ServingOffloadWLAN, LowQ).

2. In the target WLAN:

-   -   ChannelUtilizationWLAN<Thresh_(ChannelUtilizationWLAN, Low); and    -   BackhaulRateDLWLAN>Thresh_(BackhaulRateDLWLAN, High); and    -   BackhaulRateULWLAN>Thresh_(BackhaulRateULWLAN, High); and    -   BeaconRSSI>Thresh_(BeaconRSSIWLAN, High).

Similarly, according to the 3GPP Release 12 Framework, the following RRCrules may determine traffic steering from WLAN to LTE (or E-UTRAN):

3. In the source WLAN:

-   -   ChannelUtilizationWLAN>Thresh_(ChannelUtilizationWLAN, High);        and    -   BackhaulRateDLWLAN<Thresh_(BackhaulRateDLWLAN, Low); and    -   BackhaulRateULWLAN<Thresh_(BackhaulRateULWLAN, Low); and    -   BeaconRSSI<Thresh_(BeaconRSSIWLAN, Low).

4. In the target E-UTRAN cell:

-   -   RSRPmeas>Thresh_(ServingOffloadWLAN, HighP); or    -   RSRQmeas>Thresh_(ServingOffloadWLAN, HighQ).

The above RRC rules refer to the following values, presented with theirassociated descriptions:

Value Description ChannelUtilizationWLAN WLAN channel utilizationBackhaulRateDLWLAN WLAN download bandwidth BackhaulRateULWLAN WLANupload bandwidth BeaconRSSI WLAN beacon received signal strengthindication RSRPmeas Qrxlevmeas (measured cell RX level value) in RRCidle mode, and PCell RSRP in RRC connected mode RSRQmeas Qqualmeas(measured cell quality value) in RRC idle mode, and PCell RSRQ in RRCconnected mode

The above RRC rules also refer to the following RAN assistanceparameters, presented with their associated descriptions:

Parameter Description Thresh_(ServingOffloadWLAN,LowP) RSRP threshold(in dBm) used by the UE for traffic steering from E-UTRAN to WLANThresh_(ServingOffloadWLAN,HighP) RSRP threshold (in dBm) used by the UEfor traffic steering from WLAN to E-UTRANThresh_(ServingOffloadWLAN,LowQ) RSRQ threshold (in dB) used by the UEfor traffic steering from E-UTRAN to WLANThresh_(ServingOffloadWLAN,HighQ) RSRQ threshold (in dB) used by the UEfor traffic steering from WLAN to E-UTRANThresh_(ChannelUtilizationWLAN,Low) WLAN channel utilization (BSS load)threshold used by the UE for traffic steering from E-UTRAN to WLANThresh_(ChannelUtilizationWLAN,High) WLAN channel utilization (BSS load)threshold used by the UE for traffic steering from WLAN to E-UTRANThresh_(BackhaulRateDLWLAN,Low) Backhaul available downlink bandwidththreshold used by the UE for traffic steering from WLAN to E-UTRANThresh_(BackhaulRateDLWLAN,High) Backhaul available downlink bandwidththreshold used by the UE for traffic steering from E-UTRAN to WLANThresh_(BackhaulRateULWLAN,Low) Backhaul available uplink bandwidththreshold used by the UE for traffic steering from WLAN to E-UTRANThresh_(BackhaulRateULWLAN,High) Backhaul available uplink bandwidththreshold used by the UE for traffic steering from E-UTRAN to WLANThresh_(BeaconRSSIWLAN,Low) Beacon RSSI threshold used by the UE fortraffic steering from WLAN to E-UTRAN Thresh_(BeaconRSSIWLAN,High)Beacon RSSI threshold used by the UE for traffic steering from E-UTRANto WLANBackground: Mobility States in Telecommunications Standards

In addition to allowing for WLAN interworking, currenttelecommunications standards provide mechanisms for quantifying orclassifying mobile device motion, i.e., the mobility of mobile devices.Here, mobility may refer not necessarily to ability for motion, butrather to motion or movement itself, as described above with regard tothe term “mobility” in the glossary section.

In particular, existing telecommunications standards have definedcertain mobility states to categorize the states of motion of mobiledevices, as determined according to various factors. The mobility stateof a mobile device may designate a degree of movement, or motion, thatthe mobile device has been determined to be experiencing (or that themobile device is estimated or anticipated to experience). For example,as of Release 8, 3GPP has defined three mobility states for mobiledevices: normal mobility, medium mobility, and high mobility. Similarly,current versions of UMTS define two mobility states: normal mobility andhigh mobility. To determine its current mobility state, a mobile device(e.g., mobile device 106) may consider the number of reselection orhandover events it has performed during a time period defined by itsnetwork. The mobility states of mobile devices may be considered invarious processes performed by the mobile devices and by the network,such as certain wireless communications operations.

Significantly, existing WLAN interworking mechanisms fail to account forthe mobility states of mobile devices in handover evaluation processes.For example, the 3GPP Release 12 Framework does not consider themobility state of the mobile device when determining whether or when toinitiate handover. This absence of motion-related considerations inhandover processes may be negligible when the mobile device isstationary, i.e., not in motion; however, if the mobile device isexperiencing a certain degree of motion (i.e., is mobile), then notaccounting for this motion may negatively affect network and deviceresources, device connectivity, and/or WLAN interworking operations ingeneral. For example, a mobile device that is in a high state of motionwhile performing offloading to a target WLAN access point may be likelyto exit the access point's coverage area prior to or soon after thecompletion of offloading, thereby wasting device or network resourcesinvolved in the offloading processes and possibly disrupting deviceconnectivity, which may necessitate further handover operations.

It may be desirable to avoid scenarios in which a mobile devicetransitions (or attempts to transition) from a cellular base station toa WLAN access point if the mobile device is unlikely to remain withinthe WLAN access point's coverage area for a reasonable amount of time.If such a transition were to occur, the mobile device may only brieflybenefit from the connection with the WLAN access point before losingthis connection, whereupon further handover to another WLAN access pointor back to the cellular base station would be required to maintain orrestore mobile device connectivity. This undesirable scenario may resultin the mobile device undergoing frequent repeated transitions, “pingponging” between WLANs and the cellular network, which may result inincreased battery usage and a degraded user experience.

The potential of a mobile device that is in a state of motion to exitthe effective range of a WLAN access point is especially worthy ofconsideration due to the shorter range of WLAN access points in general.WLAN access point coverage areas are typically much smaller than thoseof cellular (e.g., LTE or UMTS) base stations; for example, the range ofa WLAN access point may be around 100 meters in a typical outdoorconfiguration, or around only 20 to 40 meters in a typical indoorconfiguration. Even a mobile device experiencing a low degree ofmovement, e.g., a mobile device moving at about 1 m/s (3.6 km/hr), maytraverse the coverage area of an outdoor WLAN access point in less thantwo minutes, or that of an indoor WLAN access point range in half aminute.

Thus, it may be desirable to consider both motion-related aspects ofmobile devices (e.g., the mobility states of the mobile devices) andcharacteristics of WLAN access points (e.g., whether access points areindoor or outdoor configurations) in WLAN interworking systems. Theseadditional considerations may serve to improve WLAN interworking invarious ways. Embodiments described below relate to mechanisms by whichthe mobile device may consider various additional criteria intransitioning between cellular and WLAN (e.g., from cellular to Wi-Fi),such as current or anticipated mobility (movement) of the mobile deviceand a configuration or locations of proximate WLAN access points.

FIG. 9—Flowchart Diagram Cellular to Wi-Fi Handover

FIG. 9 is a flowchart diagram illustrating some embodiments of methodsfor selectively transitioning a mobile device between using differentradio access technologies (RATs). Although FIG. 9 illustrates thespecific case of offloading the mobile device from a cellular network toa Wi-Fi network, this handover flow is merely one example, and similartechniques may be used to determine transitioning to or from varioustypes of networks, such as from a short-range RAT or WLAN to a cellularnetwork (or vice versa).

At 702 the mobile device may receive information usable for trafficsteering, i.e., information usable in directing mobile devicecommunications between different wireless networks. In some embodimentscertain traffic-steering information may be generated autonomously bythe mobile device. Alternatively, or in addition, the mobile device mayreceive the information from the source network, i.e., the network onwhich it is presently operating. For example, if the mobile device iscurrently communicating over a cellular network, as in the examplescenario represented by the figure, then this information may bereceived from a cellular base station, i.e., from the cellular network.In this case, the traffic-steering information may be usable todetermine WLAN handover, e.g., offloading from the cellular network toWi-Fi.

In some embodiments, the traffic-steering information may comprisemovement-related information. The mobile device may receive informationregarding (or usable in determining) motion-related rules, thresholds,or other parameters that would assist in regulating handover operations.In particular, this information may be usable in determining the maximumdegree of mobile device motion for which it may be desirable oracceptable for the mobile device to proceed with traffic handover. Ifthe state of motion of the mobile device is categorized into one of aplurality of possible mobility states, as described above, thetraffic-steering information may then indicate acceptable or“authorized” mobility states of the mobile device, that is, the mobilitystates in which the mobile device would be allowed to perform handover.

In particular, according to embodiments illustrated by the examplefigure, the traffic-steering information received in 702 may take theform of one or more of: (1) a list of authorized mobility states forcellular to WLAN offloading; (2) a threshold of mobility state forcellular to WLAN offloading; and/or (3) a mobility state threshold perWLAN access point if there are multiple proximate access points. In someembodiments, if the cellular network is an LTE or LTE-A network, thenthe mobile device may receive this mobility state information in anSIB17 or RRCreconfiguration message. If the cellular network is a UMTSnetwork, the mobile device may receive the mobility state information inan SIB23 or UTRAN mobility information message. The receivedtraffic-steering information may also comprise a list of neighboringWi-Fi access points and respective mobility state information associatedwith each access point.

Thus, the traffic-steering information may include or account forinformation regarding one or more possible target networks, i.e.,networks to which the mobile device is considering transitioning. In theexample case of determining offloading to Wi-Fi, the traffic-steeringinformation may include or account for configuration informationregarding one or more Wi-Fi access points that are proximate to themobile device. This access point configuration information may take theform of information regarding a range of each Wi-Fi access point, e.g.,whether each Wi-Fi access point is an indoor access point with a firstsmaller range or an outdoor access point with a second larger range. Ifthe respective Wi-Fi access point has a smaller range, the mobile devicemay be required to be in a lower mobility state (e.g., lower mobilitythan a first smaller threshold) to contemplate transitioning from acurrent cellular connection to this Wi-Fi access point. If therespective Wi-Fi access point has a larger range, the mobile device maybe able to be in a higher mobility state (e.g., lower mobility than asecond higher threshold) to be considered for transitioning from acurrent cellular connection to this Wi-Fi access point. As an example,if the respective Wi-Fi access point has a smaller range, the mobiledevice may only considered to be a candidate for Wi-Fi offloading if themobile device is in the low mobility state, and thus at 702 the mobiledevice receives information indicating the low mobility state to beacceptable or authorized. If the Wi-Fi access point has a larger range,the mobile device may be considered as a candidate for Wi-Fi offloadingif the mobile device is in one of the low mobility or normal mobilitystates, and in this instance at 702 the mobile device receivesinformation indicating that the low mobility and normal mobility statesare authorized for handover.

According to various embodiments, the access point configurationinformation may be obtained and/or evaluated by various means. In theexample case of determining Wi-Fi offloading, the cellular network mayuse its own fingerprint map of Wi-Fi access points proximate to themobile device to obtain the access point configuration information,e.g., the indoor/outdoor ranges of these access points. The cellularnetwork may also (or instead) query the one or more Wi-Fi access pointsproximate to the mobile device to determine their configurationinformation.

From the access point configuration information, e.g., theindoor/outdoor ranges of the access points, the network may be able toestimate the authorized mobility state(s) that would allow the mobiledevice to transition from cellular to Wi-Fi. In some embodiments, thecellular network may also communicate the Wi-Fi access pointconfiguration information (or approximate ranges of the access points)to the mobile device, and the mobile device may use this information toassess the mobility states in which it should transition from cellularto WLAN.

Alternatively, in some embodiments the mobile device may determine itsauthorized mobility states independently. The mobile device mayautonomously detect a configuration of one or more proximate Wi-Fiaccess points, e.g., may detect whether the access points are in indooror outdoor locations using its sensor, and may then determine a range ofmobility states for possible transitioning.

At 704 the mobile device may determine its state of motion. Mobiledevice motion may be classified or quantified using one or moreparameters or values, such as a mobility or speed value, e.g., rangingfrom 1 to 10 (with 1 representing no or low mobility and 10 representinghigh mobility), among other options. In particular, the degree or natureof the mobile device's movement—namely, the speed of its movement—may becategorized as one of a plurality of possible mobile device mobilitystates as mentioned above.

In some embodiments, these possible mobility states may be based onexisting 3GPP standards, such as the existing three mobility states forLTE and the existing two mobility states for UMTS. However, it may bedesirable to increase the number of defined mobility states so that amore precise or granular determination of motion may be used forhandover decisions.

As mentioned above, current implementations of LTE define only threemobility states: normal mobility, medium mobility, and high mobility.Some embodiments as proposed herein introduce a new LTE mobility state,low mobility, to describe static or very low-motion mobile devices,i.e., mobile devices that are stationary or nearly stationary. LTEmobility states according to these embodiments then form the followinghierarchy, arranged in order from low-motion to high-motion states: lowmobility, normal mobility, medium mobility, and high mobility.

Similarly, current UMTS standards define only two mobility states: lowmobility and high mobility. In some embodiments, two additional mobilitystates are introduced such that mobile device motion is categorized intofour mobility states similar to the LTE embodiments described above.These two additional mobility states include low mobility to describestatic or low-motion devices and medium mobility to describemedium-motion devices. In this way, UMTS embodiments may use a hierarchyof mobility states similar to that proposed for LTE embodiments asdescribed above. Thus, the mobile device may be configured with thefollowing ranking of possible mobility states: low mobility, normalmobility, medium mobility, and high mobility.

Examples of mobility-related WLAN framework extensions for LTE and UMTSare shown in the appendix of the provisional application, incorporatedby reference above. Note that other embodiments may implement any ofvarious arrangements comprising existing and/or new mobility states.

In order to determine the state of motion, e.g., the mobility state, ofthe mobile device, one or more of various mechanisms may be used. Insome embodiments, the mobile device's mobility state may be dependent onthe number of cell reselections and/or handovers the mobile device hasperformed during a certain period of time. This period of time, ordelay, may be defined by the source network, e.g., by the cellularnetwork. For example, in some LTE and UMTS embodiments, the mobiledevice when in idle mode may be determined to be in the low mobilitystate if it has not performed cell reselection or handover during adelay T_CRMAX broadcast by the cellular network. In some UMTSembodiments, if the mobile device has performed at least a certainthreshold number of reselections/handovers during T_CRMAX, it may bedetermined to be in the medium mobility state instead. This thresholdnumber used for determining the medium mobility state in UMTS may bedefined by the cellular network.

Various other techniques, or combinations of techniques, may be used bythe mobile device to assess and categorize or quantify its state ofmotion, e.g., its mobility state. In some embodiments, internal sensorsor logic internal to the mobile device, such as motion sensors, agyroscope, GPS circuitry, and/or other components, may be used todetermine the nature of movement being experienced by the mobile device.In some embodiments the mobile device may use internal sensors andtriangulation techniques to determine one or more of its location,topology, and mobility state. In some embodiments the mobile device mayalso utilize information regarding which applications are currentlyexecuting to aid in assessing its mobility state. For example, an activemap/navigation application, e.g., providing driving instructions for aselected route from point A to point B, may indicate a high mobilitystate.

In some embodiments, the mobile device may estimate its future mobilitystate, and use information regarding one or both of its current mobilitystate and its future mobility state to assess whether to performhandover. Estimation of future mobility state (e.g., estimation ofmobility state over the next 5 to 60 minutes) may be based on heuristicsand detected patterns of previous behavior.

In various embodiments and scenarios the mobility state determination at704 may take place before or after the mobile device receives thetraffic-steering information at 702.

At 706 the mobile device may evaluate the traffic-steering informationreceived at 702 in conjunction with its state of motion as determined at704 to determine whether or how to proceed with handover operations. Inparticular, if considering offloading to Wi-Fi, at 706 the mobile devicemay determine whether its current mobility state as determined at 704 iswithin the range of mobility state(s) provided by the cellular networkat 702, e.g., for a specific candidate Wi-Fi access point. If so, thenthe access point becomes a candidate for Wi-Fi offloading, i.e., fortransitioning from cellular to Wi-Fi. If the mobile device's mobilitystate is not within the range of authorized mobility states for theWi-Fi access point, the mobile device may (at least temporarily)discontinue considering handover to the Wi-Fi access point, and mayproceed to operate over the cellular network and/or to considertransitioning to other Wi-Fi access points.

If the current mobility state of the mobile device is within the rangeof mobility state(s) provided by the cellular network, then at 708 themobile device may proceed to perform further handover evaluation. Herethe mobile device may perform various WLAN measurements and/or evaluateWLAN radio resource control (RRC) rules to assess the desirability(e.g., the signal strength) of the Wi-Fi network (the proximate Wi-Fiaccess point). Example RRC rules according to existingtelecommunications standards are detailed above.

By performing further handover evaluation operations only afterevaluating its state of motion, the mobile device expends power toperform these handover operations (e.g., to further evaluate the targetWi-Fi access point by determining its signal strength, etc.) if themobility state of the mobile device indicates that a transition fromcellular to Wi-Fi would be possible or desirable. Thus, if the currentmobility state of the mobile device is sufficiently high such that Wi-Fioffloading would not make sense, then the mobile device may not performWLAN measurements and/or handover evaluation at 708.

According to some embodiments, if the mobility state is deemed too high(e.g., higher than a threshold), the mobile device may (temporarily)disable WLAN monitoring processes and/or scanning for Wi-Fi offloading.If the current mobility state later becomes lower than a threshold, themobile device may re-enable WLAN monitoring processes and scanning forWi-Fi offloading. This may serve to reduce battery power expenditure ofthe mobile device, since the mobile device may not waste powerperforming WLAN measurements, access point scanning, or RRC rulesevaluation in situations where it is moving too quickly to justifyperforming or attempting to perform handover. (Embodiments thatintegrate motion/mobility considerations into handover evaluations,e.g., into existing RRC rules, rather than evaluate motion/mobilityprimarily as a prerequisite to these evaluations, are described belowwith regard to FIG. 10.)

At 710 the mobile device may selectively transition from the sourcenetwork, e.g., the cellular network, to the target network, e.g., theWi-Fi access point, based on various factors, including one or more ofthe WLAN measurements performed at 708, cellular connection signalstrength measurements, and the current mobility state of the mobiledevice. The mobile device may evaluate WLAN/cellular traffic-steeringcriteria previously discussed and present in current telecommunicationsstandards, among other possible information.

FIG. 10—Flowchart Diagram Cellular to Wi-Fi Handover

FIG. 10 is a flowchart diagram illustrating further embodiments ofmethods for selectively transitioning a mobile device between usingdifferent radio access technologies (RATs). As with FIG. 9, FIG. 10illustrates the specific case of offloading the mobile device from acellular network to a Wi-Fi network, although similar techniques may beused to determine transitioning to or from various types of networks,such as from a short-range RAT or WLAN to a cellular network (or viceversa). In particular, according to embodiments illustrated in FIG. 10,factors regarding the state of motion (e.g., the mobility state) of themobile device are incorporated into handover evaluation processes,rather than evaluated primarily as a precursor or prerequisite tofurther evaluation processes as described with regard to FIG. 9.

At 702 the mobile device receives traffic-steering information, i.e.,information usable in directing mobile device communications betweendifferent wireless networks. As described above with regard to FIG. 9,this traffic-steering information may include information regardingproximate access points as well as allowable device motion, such asauthorized mobility states that would allow the mobile device totransition to particular access points. At 704 the mobile device maydetermine its state of motion, namely its mobility state (as describedwith regard to FIG. 9 above).

At 708 the mobile device may perform various evaluation processes todetermine whether to initiate handover. In the example scenario, inwhich the mobile device may be considering offloading to Wi-Fi, themobile device may perform WLAN measurements and/or WLAN interworkingrules evaluation, such as the RRC rules evaluation outlined in the 3GPPRelease 12 Framework as described above. Motion-related considerationsmay be incorporated into these evaluations. For example, the mobiledevice's mobility state may be introduced directly in theabove-described WLAN interworking rules for offloading from LTE to Wi-Fias follows (the bolded text indicates the addition):

1. In the E-UTRAN serving cell:

-   -   RSRPmeas<Thresh_(ServingOffloadWLAN, LowP); or    -   RSRQmeas<Thresh_(ServingOffloadWLAN, LowQ).    -   AND    -   mobility state<WLAN-Mobility-Threshold-r12; or    -   mobility state=WLAN-Mobility-State-r12.

2. In the target WLAN:

-   -   ChannelUtilizationWLAN<Thresh_(ChannelUtilizationWLAN, Low); and    -   BackhaulRateDLWLAN>Thresh_(BackhaulRateDLWLAN, High); and    -   BackhaulRateULWLAN>Thresh_(BackhaulRateULWLAN, High); and    -   BeaconRSSI>Thresh_(BeaconRSSIWLAN, High).

Additionally, the mobile device may incorporate one or moremotion-related scaling factors in its determination at 708. In otherwords, determined device movement may be used to adjust certainhandover-related measurement or threshold values such that more motionleads to more stringent conditions for handover, making handover lesslikely, and less motion allows for handover in less stringentconditions, making handover more likely. For example, according to someembodiments related to WLAN interworking, scaling factors associatedwith device motion may be used to adjust or “scale” the amount of RSSI(Received Signal Strength Indication) required for Wi-Fi offloading. Ifthe mobile device is in a higher mobility state (is determined to bemoving more quickly) then a larger amount of Wi-Fi RSSI may be requiredto render Wi-Fi offloading desirable. Conversely, if the mobile deviceis experiencing a low degree of motion, it may be desirable to performhandover despite low RSSI values, and less Wi-Fi RSSI may be requiredfor offloading.

In some embodiments, scaling RSSI rules to account for device mobilitymay be accomplished by adjusting the beacon RSSI value associated with aparticular Wi-Fi access point (i.e., the BeaconRSSI value in the aboveRRC rules) and/or the relevant RSSI threshold to which it is compared(i.e., the Thresh_(BeaconRSSIWLAN, High) value in the above RRC rules).For example, in a scenario where the device is determined to be in ahigh state of motion, i.e., a high mobility state, theThresh_(BeaconRSSIWLAN, High) value may be adjusted upwards (e.g.,according to a scaling factor associated with the mobile device's highermobility state), thereby requiring a higher RSSI value to initiate orallow for handover. In a low-mobility scenario, theThresh_(BeaconRSSIWLAN, High) value may be scaled downwards to makehandover more likely. A similar scaling factor may be used to directlyadjust RSSI values associated with particular Wi-Fi access points(instead of the RSSI threshold value), i.e., to adjust the RRC rules'BeaconRSSI value. If the mobile device is in a high mobility state, theBeaconRSSI value may be adjusted downwards so that the connectionquality with the Wi-Fi access point may be required to be moreattractive for handover in order to compensate for the mobile device'shigh state of motion, which detracts from the desirability of handover.Conversely, if the mobile device has a lower mobility state, theBeaconRSSI may be adjusted upwards.

According to various embodiments, the above-mentioned scaling factorsmay be maintained or modified by the mobile device and/or received fromthe cellular network, e.g., as part of the traffic-steering informationreceived at 702. In some LTE embodiments, motion-related scaling factorsmay be conveyed to the mobile device using SIB17 or RRCreconfigurationmessages. In UMTS embodiments, scaling factors may be sent in SIB23 orUTRAN mobility information messages. According to some embodiments, thescaling factor values may be associated with corresponding mobilitystates. For example, in embodiments with four mobility states, eachmobility state may be associated with one of four corresponding scalingfactor values. Alternatively, there may be a greater number of possiblescaling factor values, each corresponding to an estimated range of aproximate Wi-Fi access point.

At 722 the mobile device may determine whether it should performhandover based on the handover evaluation performed at 708. For example,the mobile device may determine when or whether to transition fromcellular to Wi-Fi based on one or more of the WLAN measurements/rulesevaluation performed at 708, the Wi-Fi mobility range informationreceived at 702, and the mobility state determined at 704, among otherpossible criteria. As described above, one or more scaling factors maybe used such that an increased amount of Wi-Fi RSSI is needed fortransitioning from cellular to Wi-Fi when the mobile device is in ahigher mobility state.

If at 722 the mobile device determines that it should initiate handover,then at 724 the mobile device may proceed with handover and transitionfrom the source network, e.g., the cellular network, to the targetnetwork, e.g., the Wi-Fi network. Thus, at 724 the mobile device mayfinally offload from the cellular base station to a Wi-Fi access pointin order to perform wireless communications over a Wi-Fi connection.

Embodiments of the present disclosure may be realized in any of variousforms. For example, various embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Other embodiments may berealized using one or more programmable hardware elements such as FPGAs.For example, some or all of the units included in the mobile device maybe implemented as ASICs, FPGAs, or any other suitable hardwarecomponents or modules.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE) may be configured to includea processor (or a set of processors) and a memory medium, where thememory medium stores program instructions, where the processor isconfigured to read and execute the program instructions from the memorymedium, where the program instructions are executable to implement anyof the various method embodiments described herein (or, any combinationof the method embodiments described herein, or, any subset of any of themethod embodiments described herein, or, any combination of suchsubsets). The device may be realized in any of various forms.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. A mobile device, comprising: a first radioconfigured to communicate wirelessly with a cellular base station over acellular link; a second radio configured to communicate wirelessly witha wireless local area network (WLAN) access point over a WLAN link;wherein the mobile device is configured to: receive informationregarding cellular/WLAN offloading; determine a level of allowablemotion for offloading based at least in part on the received informationregarding cellular/WLAN offloading, wherein the level of allowablemotion for offloading indicates a maximum amount of movement at whichthe mobile device is allowed to transition from the cellular basestation to the WLAN access point; determine a level of device motion,wherein the level of device motion indicates an amount of movement ofthe mobile device; compare the level of device motion to the level ofallowable motion for offloading; determine a measured received signalstrength indicator (RSSI) of the WLAN access point; compare the measuredRSSI of the WLAN access point to an RSSI threshold, wherein the mobiledevice uses at least one scaling factor to adjust one or more of anamount of the measured RSSI or the RSSI threshold; determine whether themobile device should transition from the cellular base station to theWLAN access point based at least in part on the comparison between themeasured RSSI of the WLAN access point to the RSSI threshold and on thecomparison between the level of device motion and the level of allowablemotion for offloading, wherein the mobile device determines not totransition if the level of device motion exceeds the level of allowablemotion for offloading; and selectively transition from the cellular basestation to the WLAN access point based on the determination.
 2. Themobile device of claim 1, wherein the at least one scaling factor isbased on a configuration and/or estimated range of the WLAN accesspoint.
 3. The mobile device of claim 1, wherein the informationregarding cellular/WLAN offloading comprises information regardingauthorized mobility states of the mobile device for transitioning fromthe cellular base station to the WLAN access point; wherein the at leastone scaling factor comprises a scaling factor for each of at least aplural subset of the mobility states.
 4. The mobile device of claim 1,wherein in determining whether the mobile device should transition fromthe cellular base station to the WLAN access point, the mobile device isconfigured to perform a radio resource control rules evaluationprocedure; and wherein the comparison of the level of device motion tothe level of allowable motion for offloading is performed as part of theradio resource control rules evaluation procedure.
 5. The mobile deviceof claim 1, wherein the information from the cellular base stationregarding allowable motion for offloading is conveyed to the mobiledevice using a system information block (SIB) type 17 (SIB17) orRRCreconfiguration message if the cellular base station operates usingLTE, or an SIB type 23 (SIB23) or Universal Terrestrial Radio AccessNetwork (UTRAN) mobility information message if the cellular basestation operates using Universal Mobile Telecommunications Service(UMTS).
 6. An apparatus for managing the radio access of a wirelessdevice, the apparatus comprising: a non-transitory memory medium; atleast one processing element operatively coupled to the non-transitorymemory medium, wherein the processing element is configured to executeprogram instructions stored on the non-transitory memory medium to:receive traffic-steering information from a cellular base station,wherein the traffic-steering information is usable in transitioning theapparatus between a cellular radio access technology (RAT) and ashort-range RAT; generate mobility information, wherein the mobilityinformation indicates an amount of movement of the apparatus; determinea measured received signal strength indicator (RSSI) of the short-rangeRAT; compare the measured RSSI of the short-range RAT to an RSSIthreshold, wherein the mobile device uses at least one scaling factor toadjust one or more of an amount of the measured RSSI or the RSSIthreshold; determine whether the apparatus should transition between thecellular RAT and the short-range RAT based at least in part on each ofthe comparison between the measured RSSI of the short-range RAT to theRSSI threshold, the traffic-steering information, and the mobilityinformation; and selectively transition between the cellular RAT and theshort-range RAT based on the determination.
 7. The apparatus of claim 6,wherein the generated mobility information is based on a number ofhandover or reselection events the apparatus has performed over a timeinterval, wherein a higher number of handover or reselection eventsindicates a higher amount of movement and a lower number of handover orreselection events indicates a lower amount of movement.
 8. Theapparatus of claim 6, wherein the generated mobility information isbased on internal sensors or logic internal to the apparatus, such asone or more of one or more motion sensors, gyroscopes, globalpositioning system (GPS) circuitry, and/or other components.
 9. Theapparatus of claim 6, wherein the at least one scaling factor is basedat least in part on the generated mobility information.
 10. Theapparatus of claim 6, wherein the processing element is furtherconfigured to receive information from the cellular base stationregarding scaling factors, and wherein the at least one scaling factoris based at least in part on the information regarding scaling factors.11. The apparatus of claim 6, wherein the short-range RAT is a wirelesslocal area network (WLAN) provided by a WLAN access point, and whereinthe at least one scaling factor is applied to one of a beacon RSSI value(BeaconRSSI) associated with the WLAN access point or aThresh_(BeaconRSSIWLAN, High) value associated with the WLAN accesspoint.
 12. A method for managing the radio access of a wireless device,the method comprising: receiving, at the wireless device,traffic-steering information, wherein the traffic-steering informationis usable in transitioning the wireless device between a cellular radioaccess technology (RAT) and a short-range RAT; generating mobilityinformation, wherein the mobility information indicates an amount ofmovement of the wireless device; determining a measured received signalstrength indicator (RSSI) of the short-range RAT; comparing the measuredRSSI of the short-range RAT to an RSSI threshold, wherein the wirelessdevice uses at least one scaling factor to adjust one or more of anamount of the measured RSSI or the RSSI threshold; determining whetherthe wireless device should transition between the cellular RAT and theshort-range RAT based at least in part on each of the comparison betweenthe measured RSSI of the short-range RAT to the RSSI threshold, thetraffic-steering information, and the mobility information; andselectively transitioning between the cellular RAT and the short-rangeRAT based on the determination.
 13. The method of claim 12, wherein thetraffic-steering information is generated at least in part based onaccess point configuration information, wherein the access pointconfiguration information is based on a configuration and/or estimatedrange of one or more access points of the short-range RAT proximate tothe mobile device.
 14. The method of claim 13, wherein the access pointconfiguration information indicates whether each of the one or moreshort-range access points is an indoor or outdoor access point.
 15. Themethod of claim 13, wherein the traffic-steering information is receivedfrom the one or more access points.
 16. The method of claim 12, whereinthe traffic-steering information is received from a cellular basestation.
 17. The method of claim 12, wherein the mobility informationcomprises a current mobility state, wherein determining whether thewireless device should transition between the cellular RAT and theshort-range RAT based at least in part on the mobility informationcomprises determining that the current mobility state is an authorizedmobility state.
 18. The method of claim 17, wherein the current mobilitystate comprises one of: low mobility, normal mobility, medium mobility,and high mobility.
 19. The method of claim 12, wherein the short-rangeRAT is a wireless local area network (WLAN) RAT.